# -*- coding: UTF-8 -*-
from typing import List
from leetcode_helper import TestcaseHelper, SolutionBase


class Solution(SolutionBase):
    # 解题的方法，命名和Leetcode的保持一致即可
    def countPairs_BruteForce(self, deliciousness: List[int]) -> int:
        def is_good_meal(meal_value) -> bool:
            if (meal_value & (meal_value - 1)) == 0:
                return True
            else:
                return False

        count = len(deliciousness)
        meals_count = 0

        for i in range(count):
            for j in range(i + 1, count):
                meal_value = deliciousness[i] + deliciousness[j]
                if is_good_meal(meal_value):
                    meals_count += 1

        return meals_count

    def countPairs(self, deliciousness: List[int]) -> int:
        meal_dict = {}
        mod = 10 ** 9 + 7
        ans = 0
        for i in range(len(deliciousness)):
            meal = deliciousness[i]

            for k in range(1, 22):
                pair = 2 ** k - meal
                if pair < 0:
                    continue
                if meal_dict.get(pair, -1) != -1:
                    ans += meal_dict[pair]
            meal_dict[meal] = meal_dict.get(meal, 0) + 1

        return ans % mod


if __name__ == '__main__':
    solution = Solution()

    # 按照leetcode的题目说明，将基本的test case填入
    # 每条case的最后一个元素是正确的结果，即期待的结果
    # 使用元组来保存输入的数据，期待的结果
    testcases = [
        ([1, 3, 5, 7, 9], 4),
        ([1, 1, 1, 3, 3, 3, 7], 15)
    ]

    for case_item in testcases:
        # 获取测试用的case和期待的执行结果
        input1 = case_item[0]
        expect = case_item[len(case_item) - 1]
        exec_result = solution.countPairs(input1)

        # 判断执行结果，输出提示信息
        check_result = solution.check_result(expect, exec_result)
        TestcaseHelper.print_case(check_result, case_item, exec_result)

